At present, when designing an antenna system for a mobile terminal having a metal frame, an active antenna unit at a radio frequency feeding end on the main board is generally adopted as a first radiator of the antenna system. The antenna unit is indirectly coupled with the metal frame, so that the metal frame serves as a second radiator. Through cooperation of the two radiators, resonance generated by the antenna system can satisfy bandwidth requirements.
However, such a manner has requirements on the coupling distance between the antenna unit and the metal frame, when the display screen of the mobile terminal adopts a curved screen, a position for adhering the curved screen will occupy the coupling space between the antenna unit and the metal frame. Therefore, the coupling excitation effect between the antenna system and the metal frame will be influenced, which may influence radiation performance of the antenna system. In addition, a clearance area on the main board will also influence the coupling excitation between the antenna unit and the metal frame. Specifically, the smaller the clearance area on the main board is, the more the metal elements arranged on the main board is. These metal elements may cause decreasing of the coupling excitation effect between the antenna unit and the metal frame, leading to poor radiation performance of the antenna system.